Soon you may be able to fit an X-ray machine in
the palm of your hand. An inexpensive radiation source the size of
a stick of gum has been developed by University of Missouri
researchers to make handheld scanners or tricorders as they are
being called, possible. A prototype for these scanners could be
ready in about three years.

The compact radiation source developed by
researchers at the University of Missouri. (Image via Peter
Norgard, University of Missouri)

So why would we want portable handheld X-ray
machines?

“Currently, X-ray machines are huge
and require tremendous amounts of electricity,” said
Scott Kovaleski, associate professor of electrical and computer
engineering at the University of Missouri. “The
cell-phone-sized device could improve medical services in remote
and impoverished regions and reduce health care expenses
everywhere.”

Tiny X-ray generators would be safer to use. In
dentist offices, they could be used to capture images inside of a
patient’s mouth in order to shoot the rays outward and
reduce exposure to the head.

Portable scanners could also be used to search
cargoes at border crossings to improve security and reduce costs.
Since they require little energy, they could potentially be used on
space rovers as well.

How it works

The device uses a crystal that produces more
than 100,000 V of electricity from only 10 V of electrical input
with low power consumption. Since the crystal requires so little
power, it could eventually be fueled by batteries. The crystal is
composed of a material called lithium niobate and amplifies the
input voltage by means of piezoelectricity.“The device is
about 10 cm long x 1 cm wide x 1.5 mm thick. When we apply a 40000
Hertz, 10 Volt, AC voltage through the thickness, an inverse
piezoelectric effect is induced, causing the crystal to expand and
shrink through the thickness,” said Kovaleski.At the high
voltage end are attached bits of sharp metal called field emitters
which emit electrons in the strong electric field produced at their
sharp tips. Once these electrons are accelerated toward a target,
the are converted into X-rays.“Using an optical camera
analogy, our x-ray source acts like a flash illuminated the subject
that might be imaged onto film or a digital image capture
device,” said Kovaleski.

Koleski does not envision that his newly
developed accelerator would be used only in X-ray machines.
“Our device is perfectly harmless until energized, and
even then it causes relatively low exposures to
radiation,” said Kovaleski.

He sees that it could also replace radioactive
materials such as radioisotopes used in drilling for oil or in
other industrial and scientific operations. These radioisotopes
could be replaced by a safer source of radiation that could be
turned off in case of emergency. ■